This application claims priority of Korea patent Application No. 99-66830, filed on Dec. 30, 1999.
(a) Field of the Invention
The present invention relates to a battery module structure for an electric vehicle, and more particularly, to a battery module structure for an electric vehicle in which an air plate is provided between battery cells to improve cooling efficiency and minimize the accumulation of heat.
(b) Description of the Related Art
Rechargeable batteries are provided in an electric vehicle. However, because of limitations in capacity and size of a single battery, a plurality of battery cells is grouped together into a single mechanical and electrical unit called a battery module. These modules are electrically connected to form a battery pack, which powers the electronic drive systems.
As shown in FIG. 4, a conventional battery module 51 is realized by grouping together a plurality of battery cells 50. The battery cells 50 are arranged side by side, and an end plate 52 is provided on both ends of the group of the battery cells 50. A band 53 connects the end plates 52 on two opposing sides of the group of the battery cells 50.
However, in order to provide a uniform voltage and ensure a long life of the cells 50 that make up the battery module 51, it is necessary to maintain a uniform environment for all of the cells 50. In particular, a difference in voltage occurs when the temperature of the cells 50 varies which results from the accumulation of heat.
If one of the cells 50 is significantly damaged by heat, the damaged cell 50 acts as a resistor such that high temperature heat is generated. This causes damage to an adjacent cell 50, ultimately resulting in damage to the entire battery module 51. At this time, each cell 50 exhibits a substantial difference in voltage such that undesirable effects are provided to drive motors (not shown) of the electric vehicle.
In the above battery module 51, areas where the heat is concentrated are shown by temperature contour lines 54 of FIG. 5. This results in damage to the cells 50 and a difference in temperature in the battery module 51 such that a large voltage difference is generated.
The present invention has been made in an effort to solve the above problems.
It is an object of the present invention to provide a battery module structure for an electric vehicle in which an air plate is provided between battery cells to improve cooling efficiency to minimize a difference in temperature caused by the accumulation of heat.
To achieve the above object, the present invention provides a battery module structure for an electric vehicle comprising a plurality of battery cells arranged adjacent to one another to form a group of battery cells; an end plate provided on each end of the group of the battery cells; one or more bands provided on opposing sides of the group of the battery cells, the bands being fastened to the end plates; an air plate interposed between each pair of battery cells; and a fan unit provided on top of the battery module, the fan unit blowing air onto the battery module.
According to a feature of the present invention, each air plate is rectangular in shape and an air passageway is formed within each air plate extending a length of the same.
According to another feature of the present invention, the air passageway increases in its concavity and decreases in width as a center point of the air passageway is approached, the center point corresponding to a center portion of the battery module where the accumulation of heat is most severe.